The formation of patterned light emitting layers is an important but difficult step in the production of electroluminescent devices. For example, the formation of separate red, green and blue patterned emitter layers is typically required in the production of electroluminescent full color display devices. Vacuum evaporation (e.g., using a shadow mask) is the most common technique to form each of the patterned layers. Because of the complexity and cost of this technique, particularly for use in making large format displays, other methods of forming patterned layers are needed in the art. Methods based on depositing materials from solution are especially desirable for their expected compatibility with large scale device fabrication.
Ink jet printing techniques have been suggested for producing patterned emitter layers. Depositing two colors of patterned emitter precursors by ink jet printing, followed by depositing a third color of emitter by solution techniques has been reported. However, the use of ink jet printing techniques to deposit patterned layers is limited by factors including solubility, wetting, and uniformity of the materials being deposited in the ink jet media.